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KR-102962774-B1 - Human detection method using UWB radar

KR102962774B1KR 102962774 B1KR102962774 B1KR 102962774B1KR-102962774-B1

Abstract

A method for detecting a human body using UWB radar is provided. A radar signal processing method according to an embodiment of the present invention receives a radar signal, acquires data, removes a linear trend from the acquired data, differs background data from the acquired data, and differs clutter data from the differed data. By doing so, by processing the received radar signal by first differencing the background and secondly differing the clutter, it is possible to detect a target with high accuracy.

Inventors

  • 구기원
  • 이정기
  • 양철승
  • 박진수
  • 정지성

Assignees

  • 한국전자기술연구원

Dates

Publication Date
20260511
Application Date
20211123

Claims (8)

  1. A step in which an acquisition unit receives a radar signal and acquires data; A trend removal unit, a step of removing a linear trend from the acquired data; A background difference operation unit, a first difference step of differentiating background data from acquired data; and A clutter difference operation unit includes a second difference step for differentiating clutter data from the data differentiated in the first difference step; and Background data is, It is data obtained by weighting the previous background data and the acquired data, and The sum of the first weight applied to the previous background data and the second weight applied to the acquired data is 1, and Clutter data, It is data obtained by weighting the sum of the previous clutter data and the data differed in the first difference step, and The sum of the third weight applied to the previous clutter data and the fourth weight applied to the data differentiated in the first difference step is 1, and The removal step is, Setting the average level of the acquired data to 0, The radar signal processing method is, The human body detection unit further includes a step of detecting a human body by cross-correlating with the data calculated in the second difference step. Radar signals are, It is a UWB radar signal, The clutter difference operation unit is, A radar signal processing method characterized by applying a Singular Value Decomposition (SVD) algorithm when differentiating clutter data.
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  8. An acquisition unit that receives radar signals and acquires data; A trend removal unit that removes linear trends from acquired data; A background difference operation unit that differentiates background data from acquired data; and A clutter difference operation unit that differentiates clutter data from the differentiated data in the background difference operation unit; is included, Background data is, It is data obtained by weighting the previous background data and the acquired data, and The sum of the first weight applied to the previous background data and the second weight applied to the acquired data is 1, and Clutter data, It is data obtained by weighting the sum of the previous clutter data and the data differed in the first difference step, and The sum of the third weight applied to the previous clutter data and the fourth weight applied to the data differentiated in the first difference step is 1, and The removal step is, Setting the average level of the acquired data to 0, The radar signal processing device, It further includes a human body detection unit that detects a human body by cross-correlating the data calculated by the difference operation unit in the clutter difference operation unit. Radar signals are, It is a UWB radar signal, The clutter difference operation unit is, A radar signal processing device characterized by applying a Singular Value Decomposition (SVD) algorithm when differentiating clutter data.

Description

Human detection method using UWB radar The present invention relates to UWB radar technology, and more specifically, to a method for detecting the human body without error using UWB radar. Target tracking technology is a method that detects location and relative velocity by calculating the time difference between the transmission and reception of pulses when an impulse transmission signal strikes a target and the incoming signal is received. Impulse-based Ultra Wide Band (UWB) radar technology is expected to complement existing camera-based surveillance systems by enabling precise location recognition and tracking capabilities at the tens of centimeter level indoors and outdoors at low cost and low power consumption. Meanwhile, since signals other than the received target pulse act as background noise and cause many problems in position tracking, research is needed on algorithms that can effectively remove background noise and accurately extract only the desired target pulse. Many methods for removing such background noise, or background difference algorithms, have been studied, and adaptive filter-based background difference algorithms are the most widely used. This is because background difference algorithms compare with the entire signal (moving signal), allowing for effective reflection of the moving signal. However, since errors in the motion signal (instantaneous phase changes, step effects, etc.) are reflected all at once, there is a problem where the error signal also increases. FIG. 1 is a flowchart provided to explain a UWB radar signal processing method to which the present invention is applicable, Figure 2 shows the background difference algorithm, Figure 3 is a graph showing the target movement signal, FIG. 4 is a flowchart provided for explaining a radar signal processing method applying multiple difference operations according to an embodiment of the present invention, and, FIG. 5 is a block diagram of a radar signal processing device according to another embodiment of the present invention. The present invention will be described in more detail below with reference to the drawings. An embodiment of the present invention provides a method for detecting a target (human body) using UWB radar, wherein the radar signal is processed by removing the background and clutter through multiple difference operations. FIG. 1 is a flowchart provided to explain a UWB radar signal processing method to which the present invention is applicable. As illustrated, the UWB radar signal processing method to which the present invention is applicable receives a UWB radar signal and acquires data (S10), removes the linear trend (Detrend) (S20), and performs a background difference operation (S30). Next, after undergoing a cross-correlation process (S40) on the processed data, an application (object detection and tracking, etc.) is performed (S50). In step S30, the background difference operation utilizes an adaptive filter algorithm to reconstruct the target's current position signal within the background noise using the comparison difference based on the change in the target signal between the previous and current signals caused by the moving target. The background data can be expressed by the following equation. Y i = (1-a)Y i-1 + aX i Here, Y i is the i-th estimated background data, X i is the i-th acquired data, a is a weight representing the response rate of X i , Y i-1 is the previous background data, and (1-a) is a weight representing the response rate of Y i-1 . Background difference operation is an operation that obtains difference data Z i containing only information about the target by differentiating the i-th estimated background data Y i from the i-th acquired data X i as shown in the following equation. Z i = X i - Y i The larger the weight 'a', the more quickly the waveform changes due to the target's movement can be reflected; however, when the target is stationary, the amount of information from the current received signal reflected in the background difference calculation process increases, causing the pulse amplitude to decrease and making detection difficult. On the other hand, the smaller the value of a, the more stable the position information can be maintained when the target is stationary, but when moving after stopping, the position information during the stopping period is reflected in the calculation of background noise, so the shape of the position where it stayed remains, which can cause a major problem in the position detection process. Figure 2 shows the background difference algorithm. Also, the upper part of Figure 3 shows the target movement signal that is not background differenced, and the lower part of Figure 3 shows the target movement signal that is background differenced. Meanwhile, due to the characteristics of impulse radar, signal processing is performed by storing data in fixed frame units according to distance, so errors such as voltage noise in radar signals by section and